What are the other Names for this Condition? (Also known as/Synonyms)

• Hyperactive Thyroid Gland
• Overactive Thyroid
• Overactive Thyroid Gland

What is Hyperthyroidism? (Definition/Background Information)

• Hyperthyroidism is a condition in which the thyroid gland (present in the neck) is overactive and produces too much of the hormone thyroxine, due to a variety of factors
• Thyroxine is responsible for regulating the body's metabolism. It stimulates cells of the body to produce proteins, and also increases the amount of oxygen used by them. It also has a very important role in fetal brain development
• There are two main forms of Hyperthyroidism:
  • Primary Hyperthyroidism: Hyperthyroidism is considered primary when it occurs due to dysfunction of the thyroid gland itself, and not due to factors extrinsic to the gland. This is a fairly common condition
  • Secondary Hyperthyroidism: Secondary Hyperthyroidism indicates that the dysfunction is caused by factors extrinsic to the thyroid gland (i.e., not due to a disorder within the thyroid). It is a much rarer form of Hyperthyroidism
• The cause depends on the type of Hyperthyroidism; this may include Graves’ disease (most common cause of the primary form) and thyroid stimulating hormone secreting pituitary adenoma (most common cause of the secondary form)
• The signs and symptoms of Hyperthyroidism may include rapid weight loss, irritability, heat sensitivity, diarrhea, irregular heartbeat, sweating, and fatigue. The associated symptoms of the underlying condition causing secondary Hyperthyroidism may be additionally noted
• The complications associated with Hyperthyroidism, particularly if it is unrecognized/untreated, may include osteoporosis, abnormal heart conditions, and thyroid storm or thyroid crisis
• A treatment of the condition may involve addressing the symptoms and treating the underlying cause. If necessary, the healthcare provider may administer certain anti-thyroid medications and recommend surgery too (to remove the thyroid gland)
• The prognosis is generally good with appropriate treatment, despite the requirement of medications for a lifetime in some cases. The prognosis also depends on the severity of the underlying associated condition (if any)

Who gets Hyperthyroidism? (Age and Sex Distribution)

• Hyperthyroidism is more common in females than males; most cases are diagnosed during adulthood
• The condition is prevalent around the world; all racial and ethnic groups may be affected

According to literature, the prevalence of the condition is 1.3% and 0.8% for Europe and USA respectively.

What are the Risk Factors for Hyperthyroidism? (Predisposing Factors)

The main risk factors for Hyperthyroidism include:

• Smoking
• Gender: Women are at higher risk than men for the condition

The risk factors associated with primary Hyperthyroidism include:

• Family history of Grave’s disease; the onset of Graves’ disease typically occurs between 20-25 years of age
• Very high or very low iodine intake

The risk factors associated with secondary Hyperthyroidism depend on the respective risk factors of the underlying condition.

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Hyperthyroidism? (Etiology)

The thyroid gland is a butterfly-shaped gland located in the front of the neck. It is responsible for secreting thyroid hormones that monitor our body temperature, heart rate, blood pressure, and weight. Hyperthyroidism is a condition that develops from an overproduction of the thyroid hormones due to various causes.

The most common cause of primary Hyperthyroidism is Graves’ disease. The other causes may include:

• Intake of iodine supplements
• Toxic nodular goiter
• Inflammation of thyroid gland due infections, certain medications, or pregnancy
• Carcinoma of the thyroid gland
• Toxic adenoma of thyroid gland (thyroid adenoma)

The causes associated with secondary Hyperthyroidism may include:

• Thyroid stimulating hormone secreting pituitary adenoma
• Gestational thyrotoxicosis
• Human chorionic gonadotropin (hCG) producing tumor

What are the Signs and Symptoms of Hyperthyroidism?

The signs and symptoms of Hyperthyroidism may include:

• Rapid weight loss, fatigue
• Irritability, paranoia
• Heat intolerance
• Diarrhea
• Tremors
• Thinning of skin
• Red or protruding eyes, swelling or inflammation around the eyes
• Irregular heartbeat, sweating, and palpitations
• High blood pressure

Additionally, the signs and symptoms of any associated condition (causing secondary Hyperthyroidism) may be noted.

How is Hyperthyroidism Diagnosed?

The diagnosis of Hyperthyroidism may involve the following tests and procedures:

• Complete evaluation of medical history along with a thorough physical exam
• Diagnostic tests for Hyperthyroidism may include:
  • TSH blood test
  • T3 and T4 blood test
  • TRH (thyrotropin releasing hormone) blood test
  • Radioactive iodine uptake test
  • Ultrasound scan of the thyroid gland
  • CT scan of head or MRI of brain to detect tumors in the pituitary gland
• Tests to diagnose an underlying condition may be necessary

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Hyperthyroidism?

Complications associated with Hyperthyroidism include:

• Osteoporosis: A condition causing brittle bones (easy fractures)
• Heart disorders such as abnormal heart rhythm and heart failure
• Individuals with Graves’ disease may have eyes or skin related signs and symptoms
• Thyroid storm/crisis: It is a medical emergency that needs to be treated in a hospital. In this condition, there is a sudden worsening of the symptoms of Hyperthyroidism, such as abdominal pain, fever, and decreased alertness, which may occur with an infection

How is Hyperthyroidism Treated?

The treatment of Hyperthyroidism may include:

• Symptomatic treatment through the administration of anti-thyroid medications, such as propylthiouracil and methimazole, and beta blockers
• Radioactive iodine to stop excess production of the thyroid hormones
• Thyroidectomy: Surgery to remove the thyroid gland

Undertaking treatment of the underlying cause of secondary Hyperthyroidism, such as a removal of pituitary adenoma or hCG-secreting tumor.

How can Hyperthyroidism be Prevented?

Currently, in many cases, it is not possible to prevent Hyperthyroidism.

• Knowledge about one’s family history is helpful in assessing future risks for the condition
• Individuals at risk should refrain from smoking and regularly follow-up with a physician to ensure early detection
• An early detection and prompt treatment of tumors, such as pituitary adenoma or hCG-secreting tumor, may lower one’s risk for secondary Hyperthyroidism

What is the Prognosis of Hyperthyroidism? (Outcomes/Resolutions)

The prognosis of Hyperthyroidism is generally good with appropriate treatment.

• Some individuals may either require lifelong medications to keep the symptoms under control, or a surgical removal of the thyroid gland, in case of severe and worsening condition
• In case of a surgical removal of the thyroid, it is necessary to take thyroid hormone replacements (medications) to prevent hypothyroidism, a condition of low thyroid in the body
• The prognosis of secondary Hyperthyroidism depends on the severity of the underlying cause associated with it

Additional and Relevant Useful Information for Hyperthyroidism:

• Hyperthyroidism occurs in about 1 in 250 people in the United States
• TSH in conjunction with T4 is the starting point for testing, in order to evaluate the thyroid gland function. Some of the other tests, which are performed along with TSH include tests for T3 and for thyroid antibodies

The following article links will help you understand thyroid-stimulating hormone (TSH), total T3, and total T4 laboratory tests:

http://www.dovemed.com/common-procedures/procedures-laboratory/thyroid-stimulating-hormone-tsh-test/

http://www.dovemed.com/common-procedures/procedures-laboratory/total-t3-blood-test/

http://www.dovemed.com/common-procedures/procedures-laboratory/total-t4-blood-test/